Photoelastic polarimetric stress sensing systems require signal processing in order to transform the optical signals provided by the stress sensor into an electrical signal that is proportional to the amplitude of the stress imposed on the stress sensor by the phenomenon of interest. Prior signal processing arrangements are subject to signal fading under changing environmental conditions, have a small linear dynamic range, and are adversely affected by fluctuations in the intensity of the polarized light provided by the light source of the sensing system. To deal with those undesired limitations, some prior signal processors have employed feedback to the photoelastic element to compensate for changing environmental conditions while other prior signal processors have utilized four or more optical outputs derived from the stress sensor.